Ilia Denisov
e22f4b7800
Replaces the LangUndetermined placeholder with whatlanggo-backed body detection on every send path, then adds a translation cache keyed on (message_id, target_lang) populated lazily on the per-message read endpoint. The noop translator that ships with Stage D returns engine="noop", which the service treats as "translation unavailable" — wiring a real backend (LibreTranslate HTTP client is the documented next step) is a one-file swap. GetMessage and ListInbox now accept a targetLang argument; the HTTP layer resolves the caller's accounts.preferred_language and forwards it. Inbox uses the cache only (never calls the translator) so bulk reads stay fast under future SaaS backends. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
60 lines
2.2 KiB
Go
60 lines
2.2 KiB
Go
// Package translator wraps the per-language rendering for the
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// diplomail subsystem. The package exposes a narrow `Translator`
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// interface so the actual translation backend (LibreTranslate, an
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// in-process model, a SaaS engine, …) can be swapped without
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// touching the rest of the codebase.
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//
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// Stage D ships a `NoopTranslator` that returns the input unchanged.
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// The diplomail Service treats a `Name == NoopEngine` result as
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// "translation unavailable" and refrains from writing a cache row;
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// the inbox handler then returns the original body with a
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// `translated == false` payload. The contract lets the rest of the
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// system ship without a translation backend; future stages can wire
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// a real `Translator` without code changes elsewhere.
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package translator
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import "context"
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// NoopEngine is the engine identifier returned by `NoopTranslator`.
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// The diplomail Service checks for this value to decide whether to
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// persist a `diplomail_translations` row.
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const NoopEngine = "noop"
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// Result carries one translated rendering plus the engine identifier
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// that produced it. The engine name is persisted as
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// `diplomail_translations.translator` so an operator can see which
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// backend produced each row.
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type Result struct {
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Subject string
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Body string
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Engine string
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}
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// Translator is the read-only surface diplomail consumes when it
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// needs to render a message for a recipient whose
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// `preferred_language` differs from `body_lang`. Implementations
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// must be safe for concurrent use; `Translate` may be invoked from
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// the async worker on many messages at once.
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type Translator interface {
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// Translate renders `subject` and `body` from `srcLang` into
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// `dstLang`. A nil error with `Result.Engine == NoopEngine`
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// signals that no real rendering happened.
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Translate(ctx context.Context, srcLang, dstLang, subject, body string) (Result, error)
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}
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// NewNoop returns a Translator that always returns the input
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// unchanged with engine name `NoopEngine`.
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func NewNoop() Translator {
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return noop{}
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}
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type noop struct{}
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func (noop) Translate(_ context.Context, _, _, subject, body string) (Result, error) {
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return Result{
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Subject: subject,
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Body: body,
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Engine: NoopEngine,
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}, nil
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}
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